Hello World from OSS Silicon Valley

_ Prerequisite

• Ubuntu Server installation (You can refer HowToUse/UbuntuServer/14.04)
• Ruby On Rails installation (You can refer HowToUse/RubyOnRails/4.1)

_ Install&Setup

_ Obtain Client ID and Client Secret from GitHub

Step.1

Access GitHub Developper page, and click "Register new application". [https://github.com/settings/developers]

Step.2

Input information on the new application, and click "Register Application" button. In this sample case, you can set "callback URL" as below.

http://<host name>/auth/github/callback

Step.3

Then you will get "Client ID", and "Client Secret" code for GitHub API.

_ Setup Client ID and Client Secret to your Rails project

Step.1

Edit Gemfile

$ vi Gemfile

gem 'omniauth'
gem 'omniauth-github'

(You can see sample from here.)

Step.2

Install gem files

$ bundle install

Step.3

Setup "Client ID" and "Client Secret" to environment variable.

$ vi ~/.bashrc

export GITHUB_KEY="<Client ID>"
export GITHUB_SECRET="<Client Secret>"

_ HowToUse

Step.1

Add omniauth.rb

$ vi config/initializers/omniauth.rb

Rails.application.config.middleware.use OmniAuth::Builder do
 provider :github, ENV['GITHUB_KEY'], ENV['GITHUB_SECRET']
end

(You can see sample from here.)

Step.2

Add User model.

$ rails g model user provider:string uid:string screen_name:string name:string
$ rake db:migrate

Step.3

Add method for User model.

class User < ActiveRecord::Base
  def self.create_with_omniauth(auth)
    create! do |user|
      user.provider = auth['provider']
      user.uid = auth['uid']
      user.screen_name = auth['info']['nickname']
      user.name = auth['info']['name']
    end
  end
end

(You can see sample from here.)

Step.4

Create necessary controllers.

$ rails g controller welcome index
$ rails g controller sessions

Step.5

Edit routes.

$ vi config/routes.rb

get 'welcome/index'
...
root 'welcome#index'
get '/auth/:provider/callback', :to => 'sessions#create'
post '/auth/:provider/callback', :to => 'sessions#create'
get '/logout' => 'sessions#destroy', :as => :logout

(You can see sample from here.)

You can check the configuration result from the following command.

$ rake routes

Step.6

Edit Application controller.

$ vi app/controller/application_controller.rb

class ApplicationController < ActionController::Base
 protect_from_forgery

  def login_required
    if session[:user_id]
      @current_user = User.find(session[:user_id])
    else
      redirect_to root_path
    end 
  end

  helper_method :current_user

  private
  def current_user
    @current_user ||= User.find(session[:user_id]) if session[:user_id]
  end
end

(You can see sample from here.)

Step.7

Edit Session controller.

$ vi app/controllers/session_controller.rb

class SessionsController < ApplicationController
  def create
    auth = request.env['omniauth.auth']
    user =  User.find_by_provider_and_uid(auth['provider'], auth['uid']) || User.create_with_omniauth(auth)
    session[:user_id] = user.id
    redirect_to root_path
  end

  def destroy
    session[:user_id] = nil
    redirect_to root_path
  end
end

(You can see sample from here.)

Step.8

Edit controller file which should have authentication.

class XXXController < BaseController
 before_action :login_required

(You can see sample from here.)

Step.9

Edit view file.

$ vi app/view/layout/application.rb

<% if current_user %>
  <%= current_user.name %> <%= link_to 'Logout', logout_path %>
<% else %>
  <%= link_to 'Login', '/auth/github' %>
<% end %>

(You can see sample from here.)

_ Author

S.Yatsuzuka